Dishwasher

ABSTRACT

A dishwasher operable through dishwashing and liquid drain portions of the operating cycle having a liquid drain pump that is rotated with the liquid circulation system in one direction during the washing portion of the cycle and in the opposite direction during the drain portion with at least one access passage to the drain pump through which liquid is drawn into the pump regardless of the direction of rotation thereof so that a solids collecting means in the path of flow to this one passage collects solids whether the dishwasher is operating in the dishwashing portion or the drain portion of the operating cycle.

United States Patent [72] Inventor Ival G. Dutcher 3,335,867 8/1967 Peal 210/416 Stevensville, Mich. 3,491,780 1/1970 Kaldenberg n 2lO/167X [21] p 828319 9 9 Primary Examiner-John Adee 122] Had d 2,? 5; Attorneys-James S. Nettleton, Thomas E. Turcotte, Gene A. [45] i' f j I l C Heth,Burton H. Baker, Donald W. Thomas, Frank C. [73] Asslgnee Ir poo pm-anon Harter and Hofgren, Wegner, Allen, Stellman & McCord [54] DISHWASHER 6 4 Drawmg ABSTRACT: A dishwasher operable through dishwashing and [52] U.S.Cl. 210/167, liquid drain portions f the operating cycle having a liquid 210/416; 4 134/ 1 1 l drain pump that is rotated with the liquid circulation system in one direction during the washing portion of the cycle and in 1 Field Search 310/152, the opposite direction during the drain portion with at least 416, 104, 1 11 one access passage to the drain pump through which liquid is drawn into the pump regardless of the direction of rotation [56] References C'ted thereof so that a solids collecting means in the path of flow to UNITED STATES PATENTS this one passage collects solids whether the dishwasher is 2,825,666 3/1958 Stoddard 210/ 152K operating in the dishwashing portion or the drain portion of 3,210,009 /1965 Long et al 210/416X the operating cycle.

PAIENTEUFEBmn 3565253 WYSHEETIUFZ INVENTOR. IVAL G. DUTCHER ATTORNEYS.

PATENTEU P58231971 3565 253 sum 2 BF 2 FIG?) DllSll-IWASHER One of the features of this invention is to provide an improved dishwasher with a drain pump that is rotated in one direction during the dishwashing portion of the cycle and in the opposite direction during the drain portion of the cycle and together with means for directing liquid through a passage regardless of the direction of rotation and a solids collecting means in the path of flow to this one passage for collecting solids regardless of the direction of rotation of the drain pump.

Other features and advantages of the invention will be apparent from the following description of one embodiment thereof taken in conjunction with the accompanying drawings. Of the drawings:

FIG. 1 is a front elevational view'partially broken away of a dishwasher embodying the invention.

FIG. 2 is an enlarged vertical fragmentary sectional view through the pump and cage portions of the apparatus and associated structure.

FIG. 3 is another enlarged vertical fragmentary sectional view through the pump and cage portions of the apparatus with the recirculation pump impeller and guide vanes removed showing the relationship of the filter screen to the passage leading to the drain pump.

FIG. 4 is a semischematic plan view of the drain pump and associated structure from approximately the position of horizontal line 4-4 of FIG. 2. i

In the illustrated embodiment the dishwasher comprises the usual cabinet 11 with a front 12,- control section 13, internal liquid containing tub 14 and rotatable liquid spray means in the tub or washing chamber 14 with this spray means including the customary rotatable spray arm 15.

The washing chamber 14 is provided at the bottom with a liquid collecting sump 16 having downwardly inclined sides as shown to produce a dish shape arrangement.

The bottom of the sump 116 has mounted in an opening 17 therein on supporting gaskets 18 on a motorized pump unit 19. This unit includes a motor 20 beneath the sump 16 and having a vertical shaft 21 extending up through the bottom plate 22 that spans the sump opening 17.

Mounted on the upper end of this vertical motor shaft 21 is a recirculation pump impeller 23 which draws water in from the sump 16 through peripheral openings 24 in a cage 25 and exhausts liquid upwardly between guide vanes 26 into a hollow hub 27. From the hub 27 the liquid under pressure from the pump impeller 23 is forced out into the spray arm 15 which is rotatably mounted on the top of the water flow conduit 25 that contains vanes 26. This liquid under pressure in the arm 15 is forced outwardly through openings including side openings 29 which not only spray the articles during the washing portion of the cycle but also cause rotation of the arm 15.

The liquid from the sump 16 flowing inwardly through the plurality of openings 24 as described immediately above passes first into an inner chamber 29 on its way to the recirculating pump impeller 23. The bottom of this chamber 29 in the region surrounding the motor shaft 21 is defined by a generally horizontal partition or wall 30. Immediately beneath this wall 30 is a liquid collecting chamber 31 defined on the top by the wall 30 and on the bottom by a horizontal partition 32.

Beneath this partition is a drain pump chamber 33 in which is located a rotatable drain impeller 34 of customary construction having spaced arcuate pumping vanes 35.

The impeller 34 is mounted on the shaft 21 whose central axis substantially coincides with the axis of rotation of the spray means and recirculation pump impeller 23.

Leading from selected peripheral openings 24 in the cage 25 into the liquid collecting chamber 31 of the drain portion of the apparatus are a plurality of spaced access passages 36 formed in the cage 25. In the embodiment illustrated there are three of these access passages 36 substantially equally spaced around the above described axis of rotation 37. The liquid collecting chamber 31 which is supplied by the plurality of access passages 36 communicates with the top of drain pump chamber 33 by way of an opening 33 in partition 32 which in the embodiment shown is generally circular and offcenter to the axis 37 but with the axis passing through the opening as shown in FIG. 4. As shown also in this FIG. the opening 38 in the partition 32 is arcuately closer to one of the openings 36 (identified in FIG. 4 as 360) than it is to the other two. By arcuately closer it is meant that the line shown at 39 on FIG. 4 connecting the center of the opening 38 and the axis of rotation 37 subtends an angle with the line 40 connecting the axis 37 and the center of the opening 36a which is smaller than the angle subtended between the line 39 and lines connecting the axis 37 and the center of the other two openings 36.

Located above the sump 16 and surrounding the cage 25 above openings 24 is a filter screen 46 as may be seen in FIGS. 1 and 3. The filter screen used is similar to that disclosed in U.S. Pat. No. 3,322,285 assigned to the same assignee as the present application. The filter screen 46 includes a region 45 which forms a downwardly extending passage toward the bottom edge of the cage 25. This downwardly extending region 45 terminates adjacent passage 36a in the cage 25. The region 45 is designed to provide a solids collecting region for material filtered from the washing fluid by the filter screen 46. Inasmuch as region 45 serves as a collecting region it is preferable to have the washing liquid flow downwardly through the region 45 at all times. 7 I

During the liquid drain portions of the operating cycle, the drain impeller 34 is rotated in a counterclockwise direction as indicated by the dotted line arrow 42 in FIG. 4. This rotation of the drain impeller 34 causes a flow of liquid inwardly as indicated by arrows 44 in each of the passages 36, through the chamber 31, the drain pump chamber 33, and to drain via drain line 48. Thus, any solids collected in region 45 are carried to drain.

During the dishwashing portions of the cycle, the motor 20 is operated in the clockwise direction, thus causing the recirculation pump impeller 23 and the drain pump impeller 34 to rotate in the clockwise direction as indicated by the solid line arrow 41 in FIG. 4. During this portion of the cycle liquid flows inwardly through openings 24 in cage 25, into chamber 29 and then to recirculation impeller 23. However, liquid is also present in region 31 and hence is present in the drain pump chamber 33. The drain pump impeller 34 when rotated in the clockwise direction 41 operates as an inefficient pump. The head generated by the drain impeller 34 when rotated in the clockwise direction 41 is less than the height of the loop 49 provided in the drain line 48, hence the drain is effectively blocked. Notwithstanding the blocked drain line 48 during the dishwashing portion of the cycle, a flow pattern into and out of the drain pump chamber 33 through opening 38 in partition 32 exists due to the rotation of drain impeller 34.

The flow pattern into and out of the drain pump chamber 33 during the dishwashing portion is controlled by the shape and location of the opening 38 in the partition 32 as well as the configuration of the pump chamber 33. By locating the opening 33 in the manner previously described, the flow into drain pump chamber 33 is adjacent the passage 36a.

The flow pattern into and out of the drain pump chamber 33 just described causes a corresponding flow in the drain passages 36 as indicated by arrows 43 in FIG. 4. Thus, by locating the flow into the pump chamber through opening 30 adjacent passage 36a a downward flow is assured through region 45 during the dishwashing portions as well as during the drain portions of the cycle due to the inward flow through passage 36a.

Having described my invention as related to the embodiment shown in the accompanying drawings, it is my intention that the invention be not limited by any of the details of description, unless otherwise specified.

I claim:

1. A dishwasher operable during a dishwashing portion and a liquid drain portion of an operating cycle, comprising: a washing chamber having a liquid collecting sump; a liquid recirculation pump having an impeller rotatable about an axis;

a liquid drain pump having an impeller rotatable about an axis; a liquid exhaust conduit from said drain pump; means for rotating said drain pump impeller and recirculation pump impeller in one direction during said dishwashing portion of the cycle and in the opposite direction during said drain portion; means for blocking flow through said exhaust conduit during rotation in said one direction; means forming a liquid collecting chamber adjacent said drain pump impeller; means forming a plurality of spaced access passages from said sump to said collecting chamber; a partition between said collecting chamber and drain pump impeller; means providing an opening in said partition permitting liquid flow from said collecting chamber to said drain pump impeller, said opening being closer to one of said passages than to the other with the result that there is unidirectional liquid flow in a path through said one passage regardless of the direction of rotation of said drain pump impeller; and solids collecting means in the path of flow to said one passage.

2. The dishwasher of claim 1 wherein said plurality of access passages extend substantially radially toward said axis of rotation, and said opening is arcuately closer to said one passage.

3. The dishwasher of claim 2 wherein there are three of said access passages substantially equally spaced about said axis.

4. The dishwasher of claim I wherein said recirculation pump impeller, drain pump impeller and liquid collecting chamber are substantially coaxial with said axis of rotation.

5. The dishwasher of claim 4 wherein said axis of rotation intercepts said opening in said partition.

6. The dishwasher of claim 4 wherein there are three of said access passages substantially equally spaced about said axis extending substantially radially toward said axis of rotation, and said opening is arcuately closer to said one passage. 

1. A dishwasher operable during a dishwashing portion and a liquid drain portion of an operating cycle, comprising: a washing chamber having a liquid collecting sump; a liquid recirculation pump having an impeller rotatable about an axis; a liquid drain pump having an impeller rotatable about an axis; a liquid exhaust conduit from said drain pump; means for rotating said drain pump impeller and recirculation pump impeller in one direction during said dishwashing portion of the cycle and in the opposite direction during said drain portion; means for blocking flow through said exhaust conduit during rotation in said one direction; means forming a liquid collecting chamber adjacent said drain pump impeller; means forming a plurality of spaced access passages from said sump to said collecting chamber; a partition between said collecting chamber and drain pump impeller; means providing an opening in said partition permitting liquid flow from said collecting chamber to said drain pump impeller, said opening being closer to one of said passages than to the other with the result that there is unidirectional liquid flow in a path through said one passage regardless of the direction of rotation of said drain pump impeller; and solids collecting means in the path of flow to said one passage.
 2. The dishwasher of claim 1 wherein said plurality of access passages extend substantially radially toward said axis of rotation, and said opening is arcuately closer to said one passage.
 3. The dishwasher of claim 2 wherein there are three of said access passages substantially equally spaced about said axis.
 4. The dishwasher of claim 1 wherein said recirculation pump impeller, drain pump impeller and liquid collecting chamber are substantially coaxial with said axis of rotation.
 5. The dishwasher of claim 4 wherein said axis of rotation intercepts said opening in said partition.
 6. The dishwasher of claim 4 wherein there are three of said access passages substantially equally spaced about said axis extending substantially radially toward said axis of rotation, and said opening is arcuately closer to said one passage. 